The present invention relates to an improvement in postmix fountain drink equipment, and particularly to stabilizing the palatability of mixed fountain drinks dispensed by such equipment.
"Postmix fountain drink equipment" refers to equipment designed to mix a fountain drink syrup and carbonated water at a given ratio, typically five parts water to one part syrup, on location, to produce and dispense a fountain drink comparable to a canned or bottled carbonated drink. "Postmix" is to be differentiated from "premix", which refers to mixing of syrup and carbonated water prior to delivery of the product to the location for dispensing. Premix fountain drink equipment does not require the availability of water or carbon dioxide gas other than the use of carbon dioxide gas as a pressurizing agent for delivery of the premix fountain drink product to serving valves.
Postmix fountain drink equipment, on the other hand, requires the availability of water, fountain syrup, and carbon dioxide gas for the proper operation of the equipment. To serve a palatable product, it is necessary to ensure that the proper ratio of syrup and water is obtained. For this purpose the fountain syrup is supplied to a mixing valve and at the same time carbonated water is made available at the mixing valve from a carbonator. When the serving lever is depressed, the carbonated water and syrup are dispensed into a serving container.
The carbonator, which produces carbonated water, typically involves what is known as a "venturi effect" carbonator system. This system requires a constant supply of carbon dioxide gas under pressure within a specified pressure range; typically 80 to 100 pounds per square inch. This carbon dioxide gas is supplied to a carbonator tank and water is then injected into the carbonator tank charged with carbon dioxide gas. The water is injected at a pressure above that of the CO.sub.2 gas, typically 150 to 175 pounds per square inch, to overcome the carbon dioxide charge. This interaction produces carbonated water and is referred to in the industry as "the venturi effect". The carbonated water is then supplied from the carbonator to the mixing valve and is dispensed therefrom mixed with the syrup when the valve is actuated. The correct mixture of syrup and carbonated water is set by a syrup metering adjustment on the machine valve head. Preferably the product is served at or below 40.degree. F. which is usually accomplished by using a refrigerated "ice bank" method or an "ice blanket" over a cold plate.
There are several problems relating to the palatability of fountain drinks dispensed from presently used postmix fountain drink equipment. In particular, uncarbonated products or inadequately carbonated products may be dispensed when carbon dioxide is supplied at pressure below a certain pressure or when the carbon dioxide supply is completely depleted. Typically, the venturi effect carbonators do not operate properly to adequately carbonate the water when the carbon dioxide pressure falls below 70 psi. When this occurs, the carbonator tank is filled with improperly carbonated water. The uncarbonated water is then dispensed through the mixing valve along with a quantity of syrup and an inferior drink product is dispensed. Besides the problem of a dissatisfied customer, there are other undesirable effects.
First, the low CO.sub.2 or "out of CO.sub.2 " situation may go unnoticed by the owner or operator of the dispensing machine such that numerous customers receive drinks which are not palatable, thereby reducing goodwill and even creating bad will toward the advertised manufacturer of the drink product.
The operator normally becomes aware of the out-of-carbon dioxide situation only after the fact. Because the supply lines of the postmix drink fountain equipment are filled with uncarbonated water and the syrup lines are filled with syrup, replacement of the carbon dioxide supply requires the operator to rebalance the system. This requires pulling out sufficient quantities of syrup and uncarbonated water through the mixing valve to allow carbonated water to reach the mixing valve. This wastes many ounces of valuable pure syrup. Usually a service call is required with the resultant expense and down time. Also, the energy required to cool the plain water which enters the carbonator tank and which is not used, as well as the new properly carbonated water, is wasteful and expensive.
Another problem associated with present postmix fountain drink machines arises when the water pressure supply to the carbonator pump drops below a particular minimum supply pressure value. Typically, carbonator pumps operate adequately in the range above 20 psi so that the water pressure can be increased by pump action up to the range of 150 to 175 psi. When the water pressure falls below a particular specified value, this can cause improperly carbonated fountain drinks to be dispensed because the water pressure from the pump is not high enough to permit proper venturi carbonation. Also, the carbonator tank can run completely dry such that the carbonator pump runs continuously and can easily cause the pump to burn up and require expensive service.
Once again, this situation necessitates balancing the system, including cleaning out the syrup supply lines to allow properly carbonated water to reach the mixing valve. Also, cooling the new components wastes energy.
Another problem associated with the palatability of the fountain drinks relates to maintaining an adequate supply of fountain drink syrup. When the syrup becomes depleted, the fountain drinks are dispensed as carbonated water only, or pure water only if the carbon dioxide is also depleted.
Previous references have addressed the problem of detecting when the syrup becomes depleted; but, have all failed to adequately address the problems associated with depleted supplies of carbon dioxide or water or the combination of all three components of a postmix fountain drink.
Kross et al., U.S. Pat. No. 3,940,019, relate to an automatic mixed drink dispensing apparatus which is directed primarily toward an apparatus for dispensing alcoholic mixed drinks. The Kross et al. patent shows a liquor sensing means which determines when liquor is depleted; but does not disclose or suggest means for overcoming the problem of lines filled with improper components which will be wasted and the described problems associated with inadequately pressurized carbon dioxide gas or inadequately pressurized water.
Keller et al., U.S. Pat. No. 3,112,844, relate to a measuring and dispensing apparatus for dispensing liquids from bottles using air pressure. Nothing is disclosed or suggested in the Keller et al. patent which would overcome problems associated with wasting syrup and energy in a postmix fountain drink machine when the carbon dioxide pressure falls below a predetermined level or when the other components of postmix fountain drinks become depleted.
Fuqua, U.S. Pat. No. 3,756,464, employs a pressure sensitive control valve in a premix fountain beverage system to determine when the liquid in the system becomes depleted. Nothing in Fuqua teaches or suggests means for stabilizing the palatability of fountain drinks dispensed from postmix fountain drink machines or the problems associated therewith as outlined above.
Other references to various drink mix dispensers disclose the idea of determining or measuring when the syrup becomes depleted. For example, Gust, U.S. Pat. No. 3,981,411, uses a float system. Dibell, U.S. Pat. No. 3,537,616, uses a system which weighs the liquid. Fridley, U.S. Pat. No. 3,366,276, uses a float and magnetic switch to determine the liquid level. Hanson, U.S. Pat. No. 2,880,910, uses electrodes to determine when they are no longer in contact with the liquid. None of these references relates to a postmix fountain drink system or to the problems related thereto with respect to pressurized carbon dioxide gas, or pressurized water supplied to the carbonator pump or in combination therewith, to the waste of liquid syrup caused by replenishing the depleted drink components.
Weston, U.S. Pat. No. 3,666,143, presents an improved beverage dispensing system capable of precisely dispensing predetermined volumes of beverage by varying the time the dispensing valve is opened. That system depends upon the variations in the pressure which forces liquid through the dispensing valve. Nothing in Weston teaches or discloses means or methods for overcoming the problems associated with postmix fountain drink machines.